Ignition apparatus



Sept. 1, 1953 B. H. sHQR-r Em. 2,650,581

IGNITION APPARATUS Filed NOV. 3. 1949 g .n 'n MAN/Fa mez/QM z J5@- 2 T7?Patented Sept. `1, 1953 2,650,581 IGNITION APPARATUS Brooks H. Short andArgyle G. Lautzenhiser, Anderson, Ind., assignors to General MotorsCorporation, Detroit, Mich., a corporation of Dela- Ware ApplicationNovember 3, 1949, Serial No. 125,352

(Cl. 12B- 117) Claims.

This invention relates to ignition apparatus having means for varyingthe timing oi the ignition in accordance with engine suction as wellengine speed. It has been found desirable ticularly with highcompression automobile engines to retard the ignition momentarily duringrapid acceleration. It is, therefore, an object of the present inventionto provide for momentarily decreasing the eiect of engine suction uponthe control of the ignition timer during rapid acceleration whileproviding for the normal operation of the timer to retard the sparkgradually with relatively gradual decrease of engine suction. Inaccomplishing this object, the engine provides for momentarily ventingthe pipe which connects the engine intake with a diaphragm chamberclosed by a diaphragm which moves in accordance with variations ofengine suction to control ignition timing.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing, wherein a preferred embodiment of the present invention isclearly shown.

In the drawing:

Fig. l is a diagram showing a plan view of the ignition timer with itssuction controller partly in section and a sectional view of theauxiliary apparatus for momentarily venting the pipe leading to thediaphragm chamber during rapid decrease in engine suction.

Fig. 2 is a chart illustrating the operation of the device.

Referring to Fig. l, a timer housing Iii supports a breaker plate Ilwhich supports a circuit breaker lever i2 carrying a rubbing block i3for engagement by an ignition timer cam I4 which is connected with anengine driven shaft by a device responsive to engine speed for varyingthe angular relation of the cam I4 relative to the engine driven shaftwhich has an extension i5 on which the cam I4 is rotatable.'

In the timer shown in Fig, l, the direction ci rotation of the cam I4 iscounterclockwise, therefore the speed responsive device will effectdisplacement of cam I4 relative to shaft extension I 5 in acounterclockwise direction as engine speed increases. The lever I2 isurged counterclockwise about a pivot post I6 attached to the plate I2 bya leaf spring I1 iiXed to the lever and to a bracket I8 which a wire I9connects with a terminal 20. Bracket I8 is connected also with a wire 2|connected with a condenser in a case 22, said condenser having one foilconnected with wire 2| and the othery foil with the case 22 which isgrounded by a supporting bracket 23 which a screw 24 attaches to theplate Il which in turn is connected to ground by ,a flexible wire 24soldered or brazed at 25 to the housing il and connected with a terminalclip 28 in contact with a screw 21 threaded into the plate II. Lever i2which is insulated .frem Post I6 and ,plate H wries a contact 28 forengaging a contact 29 iixed to a bracket 33 supported by a plate II. Thecondenser in case 22 is therefore in parallel with the contacts 28 and29.

The suction controller 33 of the ignition timer comprises two shells 3iand 32, the iianges of which clamp the periphery of a diaphragm 33, thecenter portion of which is attached to a link 34, a washer 35, a cup 36by a rivet 31. Link 34 is pivotally connected with plate II by the screw21. A compression spring 38 is conned between the cup 35 and a bushing35il which is threaded into a bushing 40 attached to the shell 32. Theconnection between the engine intake and the suction chamber betweenshell 32 and diaphragm 33 is provided by a pipe `4i having a restriction42. As engine suction increases, the diaphragm 33 moves right and theplate II, which is supported for rotation about the axis or" cam I4,rotates clockwise to advance the ignition timing. When engine suctiondecreases, spring 38 pushes diaphragm 33 left and the ignition isretarded.

Between the engine intake and the restriction 42, pipe 4I is connectedby pipe 43 with a suction chamber 44 located between a shell 45 anddiaphragm 41, the periphery of which is clamped between flanges of shell45 and a shell 43. Rivets 43 connect diaphragm 41 with a washer 49 and arod 50 guided for longitudinal movement by a flange 5I of shell 4E. Hole52 extends through washer 49 and diaphragm 41 and into the rod 53 andconnects with a small bleed hole 53 leading into the chamber betweenshell 43V and diaphragm 41. The hole in shell 45, which receives a rod50, is covered by a diaphragm 55, the periphery of which is clampedbetween the shell and the flange 56 of a bracket 51 secured by rivets58. Shell 51 provides a valve seat 59 for a ball valve 63 retained onthe seat by spring f3! which is located by a pin 62 attached to a shell33 supported by bracket 51 and having a vent hole 64. The valve 60 ismoved from its seat by leit movement of a rod 35 attached to a plunger6E received in a bore 61 of bracket 51, said bore being connected bypipe 63 with pipe 4i between restriction 42 and the suction device 33.

During moderate change in engine speed producing moderate change inengine suction, the diaphragm 41 remains practically in fixed positionas shown, the bleed hole `53 providing for equalization of pressure onboth sides of the diaphragm 41. Therefore, during relatively gradualincrease in engine suction, the diaphragm 33 will move to advanceignition timing as indicated by curve A in Fig. 2; and, duringrelatively gradual decrease of engine suction, the ignition is retardedas indicated by curve B. Vi/"hen engine speed is increased relativelyrapon a relatively level road, the suction in pipe il, betweenrestriction 42 and the engine will be greater than the pressure on theleft Y- Since the small hole 53 is too small to side. eiiect balance ofpressure in a relatively short time, the diaphragm l wil movemomentarily toward the left. Therefore, rod 5e will press againstdiaphragm 55 and cause left movementof the plunger S6 to move ball valve6G from its seat 53 thereby connecting pipe [il with vent through thepipe t3, bore 6l, shell di and vent hole 6K3. Therefore, there will be areduction of suction at the right of diaphragm 33 thereby permitting thespring 38 to effect momentary or abrupt retard of engine suction asrepresented by line C in Fig. 2. Restriction s2 limits the rate ofventing of that portion of pipe di between this restriction and theengine when ball valve 65 opens and hence the rate of venting chamber4d, so that the time required for equalization or pressure through thehole 53 will not extend unduly beyond the required interval of momentaryspark retarding. At the end of the period of rapid acceleration, thesuction on both sides of the diaphragm fil will have become equalized sothat diaphragm 4l will return to normal position to allow the spring Elto force valve @t on its seat 59.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted.

lv'hat is claimed is as follows:

l. Ignition apparatus comprising a timer having an engine driven timercam, a circuit breaker operated thereby for controlling ignition timing,

a plate supported for rotation about the aXis of the cam and supportingthe breaker, a rst suction operated device for rotating the plate andcomprising a suction chamber connected with the engine intake and closedby a diaphragrn connected with thefplate and a spring opposing movementof the diaphragm with increasing engine suction to rotate the plate in adirection to advance ignition timing, said spring operating to retardignition timing when suction decreases, and a separate suction actuatedmeans operating in response only to sudden decrease in engine suctioneffective on said means for momentarily venting the suction chamber toobtain ignition retard during rapid engine acceleration.

2. Ignition apparatus comprising a timer having an engine driven timercam, a circuit breaker operated thereby for controlling ignition timing,a plate supported for rotation about the axis of the cam and supportingthe breaker, a suc= tion operated device for rotating the plate andcomprising a suction chamber connected with the engine intake and closedby a diaphragm connected with the plate and a spring opposing movementof the diaphragm with increasing engine suction to rotate the plate in adirection to advance ignition timing, said spring operating to retardignition timing when suction decreases, and a device for venting thesuction chamber and including a vent valve, a spring biasing the valveinto normally closed position, a chamber having a movable partition andconnected on one side of the partition with the engine intake, meansconnected with the partition and located on the other side thereof fortrans mitting motion to the valve to open it when presn sure on theiirst mentioned side of the partition is greater than pressure on saidother Sid@ there of, and a duct through the partition providing forequalization of pressure on both sides of the partition within a timecommensurate with `relatively gradual rates of change of engine suction,said duct providing a restriction such that pressure equalization lagsbehind pressure increase on the first 'mentioned side of the partitionwhen engine suction is suddenly reduced.

3. In combination with ignition apparatus movable to advance andretarding positions of timing; a suction operated device for actuatingthe apparatus and comprising a suction chamber connected with the engineintake and closed by a diaphragm connected with the apparatus and aspring opposing movement of the diaphragm with increasing suction tomove the apparatus in a direction to advance ignition timing, saidspring operating to retard ignition timing when suction decreases; arestriction in the connection between the device and the engine intal-:eand an independent suction operated means connected around therestriction and operating in response only to sudden decrease in theengine suction eiective on said suction operated means for momentarilyventing the suction chamber to obtain ignition retard during rapidengine acceleration.

4. In combination With an ignition apparatus movable to advance andretard positions of timing, a suction Voperated device connected withthe engine intake and operable to move the apparatus to advance andretard positions of timing in accordance with engine suction, saiddevice comprising a suction chamber connected with the engine intake andclosed by a diaphragm connected with the apparatus and a spring opposingmovement of the diaphragm with increasing engine suction to operate theapparatus to advance ignition timing, said spring operating to retardignition timing when suction decreases; a restriction in the connectionbctween the suction operated device and the engine intake; and a suctionoperated valve connected around the restriction for venting the suctionoperated device momentarily to atmosphere upon sudden decrease in theengine suction which is eiiective to control the operation of saidvalve.

5. In combination with an ignition apparatus movable to advance andretard positions of timing; a suction operated device connected with theengine intake and operable to move the apparatus to advance and retardpositions or" timing in accordance with engine suction, said devicecomprising a suction chamber connected with the engine intake and closedby a diaphragm connected with the apparatus and a spring opposingmovement of the diaphragm with increasing engine suction to operate theapparatus to advance ignition timing, said spring operating to retardignition timing when suction decreases; a restriction in the connectionbetween the suction operated device and the engine intake; and a suctionresponsive by-pass means around the ree striction for venting thesuction operated device momentarily to atmosphere upon sudden decreasein the engine suction which is effective to control the operation ofsaid by-pass means.

BROOKS H. SHORT. ARGYLE G. LAUTZENHISER.

References Cited in the file of this patent UNITED STATES PATENTS YNumber

